Unhandled rejection error if source url path is bad

[estaples]

If aigis_config.yml lists an incorrect url under source:, an unhandled rejection error is returned with no direct reference to the problem file (in this case, aigis_config.yml).

It could be good to communicate to the developer that aigis can't resolve the file path.

[nakajmg]

Thank you for report !

I'll fix it on next update👍